1. Do I have to jailbreak first?
2. Have people used the hack with success?
3. How exactly do I switch the function of the large edge button and the small edge button on the left side of the K3. In other words, without affecting any other keys, how do I make the large edge button on the left do page back and the small page forward?

1. Yes, you need to install the jailbreak, then launchpad, then pageturn.
2. Yes.
3. You can't use it to do that. In the post above yours I said how to do it but I was wrong. The script doesn't change the default behavior of the keys. So you can map next page and previous page to those buttons but it will do the default action first, then the assigned one, which defeats the purpose.